Method of making current collecting devices



March 1, 1938.. H. G. FRENCH 2,109,992

METRO D OF MAKING CURRENT COLLECTING DEVICES Original Filed Nov. 15,1934 Figl.

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IV 6.19% OLA HwAttorneg V Patented Mar. 1, 1938 PATEN-Ti OFFICE METHODor MAKING CURRENT COLLECT- nv nnvrces Henry G. French, Schenectady, N.Y., assignor to General Electric Company, a corporation of New YorkOriginal application November 15, 1934, Serial 1 Claim.

My invention. relates to a method of making current collecting devices,as for dynamo-electric machines, including self-synchronizing motors andthe like.

This application is a division of my copending application Serial N o.753,115, filed November 15,

it v19:14.

Current collecting rings for self-synchronizing vmotors of the rotatablestator type are generally concentrically disposed at one end of themotor. The mounting for these rings, however, has in the past proved tobe comparatively expensive where a high degree of accuracy is required.One method previously used comprised embedding a plurality of studsabout a circle in an insulating mounting and securing, as by acountersunk rivet mounting, a collector ring to these studs.

Inorder to provide a substantially plane contact surface for the rings,they were subjected to a finishing operation when secured in position onthe insulating mounting. The various steps in manufacture combined withthe high quality of workmanship required for this method resulted in acomparatively expensive collector ring assemy.

An object of my inventionis to provide an improved method of making acollector ring assembly.

In my improved method of making the collector rings, the rings foreachassembly are stamped "from a single metal plate or disk, thematerial occupylngthe spacing between rings providing an annular anchorflange for each ring. The rings may be secured or anchored with respectto an insulating mounting by either a moulding or pressing operation.

In the moulding operation, which is preferable where a large number ofring assemblies are required, the contact faces of the rings areconcentrically positioned with respect to a single plane and aninsulating material, as a phenolic condensation product, is mouldedaround por- 'tions of these rings and anchor flanges so as se- Dividedand April 18, 1936, Serial No. 75,162

this application of the rotatable stator type provided with currentcollecting means embodying my invention; Fig. 2 is an end view, partlyin section, of the motor shown in Fig. 1; Fig. 3 is a perspective viewof one of the current collector rings, and 5 Fig. 4 is a fragmentaryview illustrating another form of my invention.

The motor illustrated by Fig. 1 comprises a rotatable stator structureI, including end shields 2, and a rotor 3. The stator l is rotatablymounted on the rotor shaft 4 as by ball bearing mountings 5. In motorsof the above-described type, the current conductors to the rotor andstator windings are led out to current collector rings mounted on andcarriedby the rotor and stator structures, respectively, the externalcircuits being completed by suitable brushes or contacts bearing on thecollector rings.

In the present instance one end shield 2 of the motor is provided with acylindrical axial exten- 2n sion within which is suitably positioned aninsulating mounting I for the stator collector rings hereinafterdescribed. A three-phase stator winding 8 is illustrated in the presentinstance, each phase tap 9 extending through an insulating bushing l 0in the end shield and through an opening in the insulating mounting lfor connection to the corresponding collector ring II.

The current leads I2 and I3 from the rotor 3 likewise extend axially ofthe motor shaft to. connect with rotor collector rings l4 and 15,respectively. These rotor collector rings are also carried by aninsulating mounting l6 secured to and rotatable with the rotor shaft.

The external circuit connections are established through resilientlymounted contacts l'l bearing individually on the ringsasxbestillustrated by spect to corresponding terminal structures I8carried'by an insulating mounting Ill. The insulating mounting plate I9is provided with a rectangular opening 20 normally closed by aninsulating cover plate 2| suitably secured as at 22 to the plate l9.

The rotor and stator collector rings in the present instance arecomposed of a high quality contact material as silver, for example, theoxide of which has comparatively low resistance. How: ever, in view ofthe cost of this contact material, it is highly desirable that thecollector rings be stamped from the blanks with as little waste materialas possible.

The rotor and stator rings for a single assemin the space between therings being turned down to form an axially extending annular right angleanchor flange", as illustrated by Fig. 3- The anchor flange, which invarious forms of my invention does not necessarily form an exact rightangle with the ring contact surface, serves a further purpose instrengthening and stiil'ening the ring itself, thereby maintaining moreaccurately the contact surface in a plane. The anchor flange 23 is inthe present instance formed I at the outer periphery of the collectorring and is stamped with dovetail notches 24 for securing the collectorring with respect to its insulating mounting in a manner presentlydescribed. The notches 24 limit the material in the flange only to thepoint where the ring is adequately stiflleads being soldered to therings at the anchor flanges 23. A suitable insulating material, as aphenolic condensation product, is thereupon moulded to the collectorrings so that the space defined by the angle between each ring and itsanchor flange is fllled with insulation to form an annular raisedportion as illustrated by Fig. 1. Accordingly the anchor flange 23 ofeach ring is permanently and securely united to the insulating mountingby the interlocking insulating portions in the anchor flange notches 24.Annular recesses 25 between the rings are formed in the insulation so asto eliminate possibility of short circuit.

The center collector ring I may obviously be in the form of a stud, asillustrated, provided with a shank which is suitably secured in theseparately moulded insulating mounting I as by screw threadedengagement.

It will, therefore, be apparent that the collector ring assemblycomprising the rotor and stator rings and insulating mountings thereforis completed at the end of the moulding operations since the ringcontact faces are positioned in substantially the same plane and,therefore, require no further machining other than possibly a lightfacing or polishing of the contact surfaces.

-The simplicity and compactness of the arrange- The arrangementillustrated by Fig.- 4 may be used to advantage when a mouldingoperation would be expensive, as where a limited number of ringassemblies are required. An insulating mounting disk 1 is turned from ablank of insulating material generally to the form of the abovedescribed moulded'support, the annular insulating flanges on which therings are mounted being undercut on one side as at 1". The collectorring II', as in the previous case, is formed with a substantially rightangle annular anchor flange 23'. A conductor 9' extending through anaperture drilled in the support I is soldered or otherwise connected tothe inner wall of the flange. The ring is secured to the support I byplacing it on the corresponding annular insulating flange and pressing,as by a spinning operation, the anchor flange into tight interlockingengagement with the undercut surface at l". The ring II is, therefore,rigidly, permanently, and accurately locked in position to itsinsulating support.- The other rings are secured to the support 1' inthe same manner and the faces of all of the rings are lightly faced orpolished.

It will be apparent that the anchor flange may be formed, in eithercase, at the inner periphery of the ring, and in the moulding operationthe flange may extend at an angle greater than 90 from the ring contactsurface.

While I have illustrated'and described two embodiments of my invention,modifications thereof will occur to those skilled in the art. I desireit to be understood, therefore, that my invention is not to be limitedto the particular arrangements and methods disclosed, and I intend inthe ap-' pended claim to cover all modifications which do not departfrom the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

A method of fabricating a current collector ring assembly whichcomprises stamping a plurality of concentric collector rings withdovetail notches around one periphery thereof from a sheet metal blank,turning in an annular portion on each of said rings on the peripheryhaving said dovetail notches to form an annular anchor flange,positioning said rings concentrically and so that the contact facesthereof are substantially in the same plane, and moulding an insulatingmaterial within the space defined by the angle between each ring and itsanchor flange so as to interlock said flanges and rings with respect tothe moulded structure.

HENRY G. FRENCH.

